Today, hair mousse is almost exclusively packaged in aluminium aerosol containers, coated internally with a high performance lacquer of PAI (polyamide-imide) chemistry. Under REACH regulations this lacquer chemistry has been classified as CMR-2 (CMR—carcinogenic, mutagenic, toxic to reproduction and category 2—strongly suspected to trigger or increase the frequency of CMR effects). There exists the possibility that the use of this material could eventually be banned under the REACH regulations. (REACH is a European Union regulation concerning the Registration, Evaluation, Authorisation & restriction of Chemicals.) Since December 2010, such material has been classified as R61 (may cause harm to the unborn child), R37/36/38 (irritating to eyes, respiratory system and skin) and must be labelled as toxic. Therefore, it is socially & environmentally responsible to avoid using such a classification of chemical, wherever possible.
WO 02/072449 A (GLAXO GROUP) Jul. 9, 2002 describes a canister for use in metered dose inhalers formed from a laminate material composed of a metal and a strengthening material. The laminate is described as providing equivalent or greater strength than ticker walled aluminium containers. However, this is different to the problem addressed by the present invention, where the container is required to store and dispense an aggressive product requiring a high performance, corrosion resistant lacquer.
U.S. 2007272768 A Nov. 29, 2007 discloses a container for pressurised materials having a multi-layer construction, particularly water-based adhesives. The inner layer is described as being resistant to corrosion from contact with water. However, this document does not discuss aggressive personal care or household products and rather is focussed on adhesives that must not be exposed to air before being expelled from the container.
EP 0854827 B (PROCTER & GAMBLE) Mar. 1, 2000 discloses an aerosol can, filled with an acidic detergent composition, and having a plastic liner to provide protection for the can. According to this patent, the liner/container assembly is filled with an aggressive product (for example an acidic detergent composition) and an aerosol propellant. The plastic liner is preferably made from a polyolefin material, more preferably high density polyethylene or polypropylene. However, this patent also notes that hydrocarbon propellants will diffuse through polyolefin materials with time.
The inventors have appreciated the benefit of using a separate liner to protect an outer aerosol container as described in this patent. In particular, the inventors noted that as long as the liner is compatible with the product or composition and propellant, the product/propellant combination may be stored within the liner, without worrying about the adverse effect of the product/propellant combination on the outer aerosol container. The use of a liner in this way provides a possible solution to the problems associated with using a high performance, but potentially toxic lacquer to coat the inside of a metal aerosol can when packaging aggressive products. Furthermore, provision of a liner allows the outer aerosol container to be produced using a wider range of materials and techniques e.g. conventional steel, aluminium or plastic containers may be provided, manufactured using known 2-piece, 3-piece or impact extrusion techniques. However, diffusion of the propellant through the liner or bag over time will gradually reduce the effectiveness of the aerosol container in dispensing the product and is unsatisfactory for a user of the aerosol can.